| Ti-Si-N thin system attracts considerable interests due to the high hardness, high elastic modulus, low friction coefficient, and exllent thermal stability. However most of the Ti-S-N films are lack of toughness. This study focus on the designing of Ti-Si-N films with high toughness based on the commercial finite element software Abaqus. The main conclusions are as the follows:1. In TiN/SiN.../TiN multilayer model, with the increase of silicon nitride phase content, the hinder of stress concentration becomes stronger.The toughness of Ti-Si-N system thin film material increase gradually.The elastic modulus of silicon nitride is more close to titanium nitride, the increase of toughness of multilayer film is more obvious. Silicon nitride and titanium nitride content remains the same, with the increases of layers, the inner layer of the local stress concentration remit, but the interlaminar stresses concentration increase, the toughness of thin film significantly increase, then remains constant.2. In columnar crystal model, after the completion of loading, with the decrease of the columnar grain size, Mises stress and shear stress S12 distribute more evenly, stress concentration decreasesgradually. After unloading, equivalent plastic strain has better dispersion. But after reaching the critical point the toughness of the film does not continue to increase sharply.3. In nano-composite structure, silicon nitride phase can hinder the expansion of the stress concentration zone, reduce the stress of throughout nanocomposite model.With the reduction of the grain size of titanium nitride, Mises stress and shear stress S12 showed a decreasing trend, the toughness of Ti-Si-N films gradually increase. When titanium nitride andsilicon nitride phase content remains the same, the toughness of nano-composite structural material is roughly equal to 16 layers columnar structure. In addition, in the deformation process, plastic strainoccurs in nano-composite structure thin film. |
PDF Full Text Request